Welcome to Chemistry

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Objective

SWBAT follow lab directions, measure accurately and work safely in a lab environment

Big Idea

Defeat the tedium of day 1 syllabus review and get students excited for science.

Introduction

Day one of the school year high school can be an exercise in tedium as students shuffle through their schedule, hearing seven different sets of procedures, policies, and syllabi.  When we got new science labs a few years ago, I decided to turn the first day into an attention getter.  Since then, the day has morphed further, and now includes a simple measurement lab.  For many of my students, this may be their first time performing a wet lab in their academic careers.  This activity allows me to pre-assess both students' measurement skills with the graduated cylinder, their ability to follow directions and their persistence if performed incorrectly the first time.

While there is not a direct correlation to the NGSS here, to perform the science and engineering practices students must have confidence and skills in lab.  This lesson allows me to evaluate some of those skills, and begin to build confidence in students immediately.  It also breaks the tedium of day 1 by getting students up and doing, thereby making chemistry the class that they talk about at the dinner table that night.

There is a connection to Cross Cutting Concept 5- Energy and matter.  We discuss both pieces during the lesson, and set the table that those concepts are the major focus of the year.  As NGSS becomes more ingrained in the earlier grades, students should be able to connect those ideas to prior knowledge right away in the first day of class.

Lab requirements per Rainbow setup:

  • 3 beakers with colored water- 25ml of each color (red, blue & yellow)
  • 2 graduated cylinders (10mL & 100mL)
  • 6 large test tubes labeled A, B, C, D, E, and F
  • 1 test tube rack
  • Goggles
  • Lab Aprons

 

Demonstration Requirements Methane mambo setup

  • Ring stand
  • Large Ring Clamp
  • Rubber hosing
  • Dish soap
  • Water
  • top half of a 2L soda bottle
  • Single Hole Stopper to fit bottle spout
  • L-shaped glass tubing
  • Aim-and-Flame lighter

Opener

10 minutes

When students enter the room, I meet them at the door where I greet them and encourage them to find a spot at a table.  Each table of four has four half sheets of paper with the Opening Survey on it, a piece of paper towel, a portable whiteboard with a marker, and the question "Why are you taking chemistry?" is written on the board.  As the bell rings, I enter and introduce myself to the class.  I follow my introduction with asking students to take a paper from the center of the table and begin to answer the questions on the paper. 

While students are writing, I go table by table to take attendance in groups of four.  This allows me the opportunity to associate names with location and faces, and to clear up any nickname preferences or pronunciation fears in the small groups.  If I notice tables are finished before I am done making the rounds, I encourage them to introduce themselves to their table mates.

Once I have made my rounds and met each student, I ask them to take the small white board and record why the members of their table are taking chemistry.  The most common response is "my biology teacher/counselor made me".  The second most common response is "I want to learn how to blow things up".  I ask each table to hold up their responses so I can view them and I'll comment on both common and unique responses.  I ask the students to then erase the board and write the response to the second question on the sheet, "How have you used chemistry in the last week?

Most students are stumped at this question until they see other responses such as cooking, cleaning, and driving.  My goal here is to drive home how chemistry is throughout our everyday experiences to set up some interest in the course.  I have the students share the responses from their tables and again reinforce common responses and highlight any unique contributions.

At this point, I tell students they are going to be doing a lab with a partner from their table.  If I have multiple tables of three, I pair up the extras rather than have groups of three working together.  I tell students that the equipment and directions are at their lab tables, and show them the help cards.  I explain that if the lab is going fine, the green side is up, but if they have a question, to flip to the red side so I can see it.  This is a procedure I use year long when students are in lab or using the computers.  I explain that all the chemicals are safe, but can stain clothing, so we will need to wear goggles and lab aprons and remain standing during the lab.  I then direct each group back to the lab table I want them to work at.

Lab

20 minutes

When students get to the lab, they can see the following equipment laid out for them:

  • 3 beakers with colored water- 25ml of each color (red, blue & yellow)
  • 2 graduated cylinders (10mL & 100mL)
  • 6 large test tubes labeled A, B, C, D, E, and F
  • 1 test tube rack

 

The lab directions are on each station.  At this point, it is up to the students to determine what each piece of equipment is and if they know how to use it.  I allow groups to help each other to figure things out.  When students are first entering the lab, I collect their opening surveys to read later. 

While students work, I circulate the room, reminding students to put away the lab stools and to wear their goggles.  Many students will want to take off their goggles to measure, and they have to get used to reading labware through their goggles.  Some groups will pour the water directly from beaker to test tube, not realizing that they need to measure using the graduated cylinders.  I will ask these groups how they know exactly how much is present in the test tube, and use this as a teachable moment about how to measure liquid chemicals.  I find it very helpful for my students to check off each step in the procedure as they go so that they do not repeat steps and introduce error.  Another common error during lab is to measure the top, rather than the bottom of meniscus, or to utilize the wrong size graduated cylinder. 

When a group is done, they should have 6 test tubes with equal volumes, and therefore heights, of liquid.  From A-F they should be Red, Orange, Yellow, Green, Blue and Purple.  The purple is often hard to make out if too much blue dye is added to the water at the start.  It is crucial to use uniform test tubes to be able to make a quick visual inspection of colors and heights -- they MUST hold at least 22 mL.  My preferred size is 18x150mm.

If the volumes are clearly different, and time permits, I encourage students to try again.  Oftentimes, the careful, experienced students will take about 15 minutes and have it turn out perfect on the first trial.  When students are finished I show them how to clean up, return their safety equipment,  and return to the front of the classroom, stopping at the front desk to pick up paperwork.  Students who finish early are encouraged to start reading through the course syllabus.

Class Policies

15 minutes

As students return to the front of the room, they collect seven papers from the front desk:

 

I always provide two copies of the safety contract, one to be signed and turned in to me, and one to be kept in the student binder.  The Spanish copies are available for students who might need it for their parents.

When all students have returned from the lab, I direct their attention to the papers.  I ask them to get the safety contracts out first.  I remind them these are the same contracts they worked with in biology the previous year, but that we will have different emphasis on certain rules this year.  I explain that they took two -- one to get signed and turned in within 3 class days, one to keep in their binder and study from for our safety exam.

Next, we look at the syllabus and I ask them to read the first paragraph as I move to the back of the room, put on an apron and goggles, and begin prepping the chemical demonstration.

This is the Methane Mambo demonstration, and the setup looks like this.

When turning the gas on, it bubbles through the soapy water, trapping methane in the bubbles.  While it is bubbling up, I ask the students if someone can operate the aim-and-flame.  I select a volunteer and have them also put on an apron and goggles.  Now I ask the students what the two parts of chemistry are from the paragraph atop the syllabus.  They will reply "matter and energy" and I ask "Which part did you work with in lab already today?"  Students should reply "matter"- at which point I explain, that we're going to deal with some energy really quickly.  I whisper the instructions to the volunteer that they will light the bubbles arched between my hands and step back.  It is CRUCIAL to wet your arms -- this protects you from burning all the hair off your hands and arms.  I shut off the gas and scoop up the bubble tower, being careful to not stand under a sprinkler or fire detector, and let the volunteer light the bubbles.  The methane burns spectacularly and the wave of heat reaches throughout the room. 

Students get extremely excited and often ask for a repeat, and if they can tape it on their phones.  I offer a repeat if they can tell me two or more ways they experienced the energy in the reaction.  Students will cite the heat, the light, and sometimes the "whoosh" sound of the flames.  If they can provide this information, I will repeat the demonstration on the condition someone send me a copy of the video.

Now we return to the syllabus and go through the required materials, how to get extra help, and I have students sign up for Remind -- a text message based online system where I can text reminders to students without either of us sharing our phone numbers.  I then explain the parent signature form and that I need the best number to reach them during class, in case of a lab accident.  This generally gets me more accurate numbers than if students think it is to call home about behavior.  This form is also due in three class days with the safety contract.

I then explain the BetterLesson project and the need for the video permission form.  This is also due in three class days.

Ice Breaker

5 minutes

With the remaining time in class, I instruct the students to complete their Three Truths and a Lie sheet.  I explain that the lie can be any one of the four items, but that all items must be school appropriate and something they wouldn't mind their grandmother reading.  I also explain that they will share them with the rest of the class.  I ask them to flip them upside down when they are done writing.

When students complete their forms, I collect them, and then model this with my own.

  • I have over 16,000 songs on my iPod
  • I have provided medical services to over 10 professional athletes
  • I have two dogs, three cats and a bird
  • I spent a week in Mexico this summer

 

I ask the students to put their hands up based on which one they think is a lie, and I repeat each option.  The lie is the third, I only have one dog.  If students ask, I can explain the others.  Time permitting, I will then pick a random student's paper from the pile, ask permission to share their paper.  If a student says no, I will replace it in the pile, but explain that at some point they will have to go.  I ask the student to stand up and I read their four items, ask the class to vote on which was the lie.  Then I have the student inform us which was the lie, and allow one or two questions about the truths from curious classmates.

I will use these throughout the next few weeks at the end of class if we have extra time, or sometimes in lieu of a bell ringer to start the class.  Building a connected classroom is critical for the amount of work we will be completing together throughout the year.  This is the first step to a safe environment where all students feel they can contribute.

It is helpful to copy each period on different colored paper, to easily keep the various classes separate.  I'll generate four or five of these myself to keep each class on their toes, and so that they can get a better feel for me as a person.